We can categorize ourselves into the four classes of ancient Indian society — brahmin, kshatriya, vaishya, and shudra — by birth, function, or inner aspiration. When we use birth as the basis, it creates the caste system, a result that is not even worth talking about. By function (responsibilities of our current job), we can classify ourselves as educators (Class I), defense professionals (Class II), entrepreneurs (Class III), and employees (Class IV). In an entirely function-based classification, our varna is not a static label — it can be voluntarily changed by switching careers.
Similarly, we may classify ourselves according to our inner aspiration* as follows:
Class I: Learning or Seeking Brahman
Class II: Protection of the Motherland
Class III: Growth of an enterprise
Class IV: Focused work on a supervised project
In an aspiration-based approach, figuring out our true class may not be that easy. Does an industrialist who desires personal profit alone belong to Class III? Can teachers or spiritual gurus aspiring for money or fame call themselves Brahmins? Nevertheless, this approach does have an advantage over the function-based approach: Except our own mind and God, no one else can recognize our class.
*The Bhagavada Gita classifies us according to our inner nature, which includes function, aspiration, and aptitude.